In today's commercial transport industry, it is highly desirable to design aircraft configurations that yield reduced fuel burn per seat-mile, as fuel burn per seat-mile is a metric of fuel efficiency. Efficient aircraft configurations are ever more important as fuel costs increase. Aircraft aerodynamic drag and fuel burn are generally reduced as the aspect ratio of the aircraft wing increases. Similarly, operating larger aircraft, carrying more passengers and payload, are generally more efficient between two destinations than flying several more trips with smaller aircraft. Thus, larger aircraft and aircraft with longer wingspans tend to be more efficient than aircraft with smaller wingspans. However, taxiway spacing and gate locations for most airports were established to accommodate aircraft with a certain wingspan.
Some attempts have been made to improve aircraft wing efficiency without adding wingspan. Winglets extending vertically from the wingtips have improved aircraft fuel efficiency without significantly increasing wingspan. However, the efficiency added by winglets may not be beneficial as that provided by extending the wingspan.
Thus, it is desired to provide an aircraft that can benefit from a long wingspan in flight, while being able to reduce the wingspan while operating at an airport.